The complete discus fish care guide continues my latest series, focusing on fish from the Amazon river basin. These fish make up are some of my favorite aquarium fish. Nowhere else in the world are colorful freshwater fish so plentiful. The purpose of this guide is to teach you everything you need to know to take care of Discus. Let me know what you think in the comments below.
Note: Discus fish and Discus are often used interchangeably in the aquarium hobby. The same is true for this guide.
Discus Fish Origins
To understand discus fish care, the first and most important step is to understand where they come from. Discus fish, or Symphysodon, as stated above, come from the Amazon river basin. They were first discovered, or named, in 1840, and since then numerous subspecies of discus have been found.
The preferred location of discus fish varies by species, but one thing is clear among all them. Discus prefer to live in floodplains, with other living organisms and trees. Here the water is free from suspended particulate matter, and kept incredibly clean through nature’s filtration system. As a result, discus fish love clean water.
Overall, these origins mean that discus fish enjoy live plants, regular large water changes, and lower pH water with some tannins.
Discus Fish Appearance
Discus fish have an incredibly unique appearance that has cemented their popularity in home aquariums.
The above image shows an incredibly high quality discus. As can clearly be seen, discus have an iconic round shape, with long fins sticking both above and below the body. They come in a variety of colors, ranging from solid colors, to beautiful patterns such as the discus above.
Discus Fish Tank Overview / Setup
Before we discuss the intricacies of Discus fish care, let’s start by discussing how to setup an aquarium for them and their generally desired water parameters.
Discus Fish Parameters:
- pH (slightly acidic): 6.0 – 7.0
- Temperature: 80 – 85 degrees Fahrenheit
- Hardness (soft) : ~2 dKH
- Schooling Fish (6 minimum)
- Size: ~7-9″
- Minimum Aquarium Size: 55-75 gallons
- Water Changes: 25-40% 2-3x weekly
For first time Discus keepers, I recommend always starting with a 75 gallon aquarium and several good sponge filters. You can potentially use a power filter on the back for additional filtration, and to give you the opportunity to add media. Remember to always start by cycling your aquarium.
As always, I recommend trying to duplicate the fish’s natural habitat in your aquarium with driftwood and live plants. Setting up a Discus aquarium will generally involve 4 steps:
- Setup the aquarium and stand on a sturdy table in a sturdy portion of your house. This is especially true for Discus aquariums. A 75 gallon aquarium has 600 pounds of water and likely close to 100-200 pounds of other items. Make sure your floor can handle this. At a minimum make sure the aquarium’s weight is distributed across multiple floor braces .
- Add the filtration system, substrate, and decorations (treated driftwood). Slowly fill up the aquarium, add your lighting system, and your plants. Take the time to properly cycle the aquarium.
- Plan your species / tank, water change cycle, and feeding cycle. Discus are expensive and difficult fish to keep and it’s always best to start with a plan of how to handle all their requirements.
- After the aquarium has been fully cycled, add them to the aquarium, taking the time to slowly transfer them. If adding them to a tank with an existing community of fish, make sure to quarantine them first.
Discus Fish Types
FishBase, despite the old looking website, is a valuable database for fish species. The website officially recognizes 3 different fish species. These are Symphysodon tarzoo, the classic green Discus, Symphysodon aequifasciatus, the blue or brown Discus, and Symphysodon discus, or the red / Heckel Discus.
For the average Discus owner, who doesn’t intend to breed their Discus, the differences between these species are unimportant. However, some breeders do tend to focus on one species of Discus, so it’s worth knowing. This is especially true if you prefer a certain species of Discus.
In general, I recommend picking a species to start with, stocking your tank with it, and sticking with it. Generally reputable Discus breeders allow you to pick and stick with a single species. For example Kenny’s Discus lists out the strain of each Discus it sells on its sale page: here.
Discus Fish Behavior
Before you stock your aquarium with Discus, it’s important to understand the behavior of Discus fish. Discus fish are schooling fish, which means despite their price, you should have at least 6 of them in the aquarium. As a result this means you should keep them in at least a 55-75 gallon aquarium.
The exception to this is a breeding pair of Discus which can be kept as a pair in a 40 gallon aquarium. However, I do not recommend breeding Discus for beginners.
Among themselves, Discus behave as the Cichlids which they are, which means that a pecking order will be established. That’s why having a school of at least 6 is so important. In a school of 2, one will be bullied by the other, oftentimes to death. Even if the Discus isn’t bullied to death, the stress is often enough to make the Discus much more susceptible to an illness.
Once the Discus establish a pecking order among the school, the aggression will wane some. It is still important to make sure that the Discus at the bottom of the pecking order are getting sufficient food, sometimes spot feeding them can help.
Lastly, in terms of Discus behavior, it’s wise to either add all the Discus to your cycled aquarium at the same time. When a new Discus is added by itself to an existing school, the pecking order can be disrupted. One way around this is to rearrange the aquarium to confuse the existing school, however, it’s still better avoid if possible.
Discus Fish Price
Among the reasons that Discus fish are well known is their price. Small Discus, in the range of 4″, that are added to a new aquarium cost roughly $60. Larger versions of popular species can be more than $100. Large versions of rarer species, or breeding pairs, can easily cost hundreds of dollars.
The reason for their cost is that Discus fish are notoriously difficult to keep. Discus require immaculate water quality, which even in large breeding setups, has significant expense. Secondly, Discus are also large fish, which means they cannot be kept at the same density. Lastly, Discus have a shallow gene pool, which means that there is a respectable amount of culling.
Despite the already high expense, I recommend always paying the prices required, and ordering Discus from a respectable breeder. Going with a less reputable breeder can result in your fish dying, or even worse, diseases being introduced to your aquarium. As a result, I recommend talking to other Discus owners to find quality breeders.
For those looking for somewhere to meet other Discus owners or shop for Discus, I recommend starting with the Simply Discus forums. I’m a huge fan of different aquarium forums, and Simply Discus is one dedicated solely to these great fish.
Discus Fish Tank Mates
Discus do fine with a number of different tank mates, especially in good sized aquariums with ample hiding spots. In general, when picking Discus tank mates, you should keep in mind 3 rules.
- No aggressive fish. Aggressive fish can stress out Discus or attack their slime coating.
- Temperature. Discus prefer warmer temperatures into the lower-80s. Make sure the other fish you stock are also okay with this.
- Location. Generally tropical fish that hail from the same South American locations as the Discus have a good chance of liking the same kind of environment.
Corydoras are some of my favorite fish to keep with Discus. Discus do a great job in the middle-upper region of the aquarium, and corydoras do great in the bottom region of the aquarium. As a result, having corydoras allow you to balance out the look of the aquarium.
Because of Discus’ temperature requirements, some particular corydoras do work better than other corydoras. For example, Sterba’s corydoras are incredibly popular to keep with Discus. They hail from some of the same areas of South America as Discus, and as a result enjoy the same environmental parameters.
I personally prefer Panda Corydoras, however, you do have to balance their temperature requirements with Discus since there is a bit of a gap.
Here are some generally great categories to look into:
- Tetras (particularly Neon Tetras or Cardinal Tetras)
- Rams (Bolivian or German Blue)
- Invertebrates (Assassin snails and red cherry shrimp)
- Agassiz’s dwarf cichlid
Keep in mind anything that can fit in the Discus’ mouth will be eaten. As a result, make sure if you want to include, say, Red Cherry Shrimp, you have to have an aquarium with plenty of hiding spots. Otherwise, you will have just provided your expensive Discus with some expensive snacks.
Here are some general categories / fish to avoid:
- Many other cichlids (i.e. Oscars)
- Clown Loach
Overall, there are plenty of great tank mates you can keep with Discus. If you have any questions about a specific species, just ask in the comments.
Discus Fish Diet
Just like their water quality and cost, Discus fish tend to demand a more nuanced diet that most fish. They are omnivores, like most other tropical fish, however, they tend to prefer a higher quality more meat based diet. They also generally need to be fed more often, especially when young. Here’s how often you should feed your Discus:
- Young (<4 months) = ~10 times / day
- Teenage (4 months – 1 year) = ~5 times / day
- Adult (> 1 year) = ~2 / day
Until Discus are more than a year old, they can be quite a lot of work to feed. I recommend, for younger Discus, using an automatic feeder if you’re gone during the day.
Generally those who feed Discus fall into two camps. All natural feeders who tend to cook food for their Discus (i.e. feeding Discus home-made beef heart using this recipe).
For simplicity purposes, we will discuss a simple feeding plan for those who don’t have the time to cook their own food. However, a quick warming to those who do plan to cook their own food. Using live food or cooking your own food could introduce parasites to the aquarium or dirty the water quicker.
I generally recommend centering your feeding plan around the following items:
- High quality, high protein flakes / pellets.
- Beef heart flakes.
- Frozen blood worms or similar.
- Spirulina flakes.
Discus need a high protein diet of at least 40% protein. Ideally, however, more than 50% if possible. Generally I recommend starting with some high quality flakes / pellets, with high protein content. Some places sell Discus specific food for a higher price, however, you can often find other food with the same nutrition content for a lower price.
Past this, I often choose to add some beef heart flakes due to their higher protein content. Adding some frozen blood worms or other frozen brine shrimp can also help keep the fish healthy, while providing them different sources of food. Lastly, I recommend some greens (Spirulina). You don’t need much, but Discus do eat algae and similar foods in the wild, and Spirulina is great at helping your Discus’ colors to shine.
Mixing different foods isn’t hard. Oftentimes, I just grab a Tupperware, mix in a bunch of different foods, and then use it to feed my fish. However, when feeding Discus, there’s a few important things to keep in mind.
- Soak the food in a bit of water. This prevents bloating for your Discus.
- Feed sparingly. Only feed your Discus what they can eat in a few minutes.
- Mix it up. I like to change thing up occasionally so that Discus aren’t always eating the same thing. In my opinion, it helps keep them less picky. Different kinds of protein can also help here (i.e. bloodworms one week then brine shrimp or white worms).
- Keep an eye. Discus aren’t as aggressive as other fish about their food, especially in a community tank. As a result, I recommend keeping an eye on things and making sure all your fish get enough food.
Discus Fish Tank Size
This was touched on some above, however, it’s worth highlighting separately.
Discus can grow to be large fish, with the largest reaching 6-7″+. Their plate like “shape” means they also like taller aquariums. On top of this, their schooling nature and water quality sensitivity mean that your aquarium will have a respectable bio load and parameters that shouldn’t vary much.
As a result, for a school of 6 Discus I would recommend a minimum 55 gallon aquarium. Generally, a good rule of thumb would be 9 gallons / fish, with a minimum of 6 fish. Ideally that’d be pushed towards 10-12 gallons / fish.
You also want to make sure any aquarium you keep Discus in, regardless of its size, is at least 18″ tall. That means the fish will have ample room above and below it as it swims through the aquarium.
Discus Fish Breeding
I also want to talk briefly about breeding Discus fish. Breeding Discus is a difficult and interesting topic, one that warrants a minimum of one, if not multiple articles of its own. However, for those familiar with spawning other species of fish, breeding Discus is often considered most similar to breeding Angelfish.
The first step to breeding Discus is to get a pair. The easiest way to do this is to purchase a proven pair online, which can often cost $500+. Alternatively, you can simply setup a Discus aquarium with 6-8 young fish, and wait for them to pair, which will happen ~1+ year mark.
Discus pairing off has multiple different signs to look out for, however, some of the most common are an aggressive fish (male) guarding one particular spot of the tank, while interacting with a female or waiting for one to approach. Discus who have paired can be seen “bowing” or interacting with each other and bending their fins.
When Discus pair off they will likely choose a spot in the tank and fend off other fish. It’s at this point, many breeders move the Discus to their own tank.
When the Discus are ready to spawn, they’ll find a particular site, and begin to clean it. Make sure you keep the lighting schedule regular, as it affects the Discus spawn time. After several days of cleaning, the Discus will lay eggs. Don’t separate the Discus from the eggs, Discus are good parents and will keep an eye on the eggs.
After 3 days or so, the eggs will hatch. The newly hatched fry will be moved around for several days. The fry will soon become free swimming and eat the mucus coat off of the parents skin. Here, it’s still important not to move the parents, as they provide a vital source of food for the fry.
Roughly three to four weeks after hatching, when the fry reach nail size, it’s time to move the parents. They’ll start to get fed up by the larger hungry babies eating their mucus constantly. It’s time to remove the parents and begin to feed the fry separately, a very high protein food. It’s also time to start treating the tank lightly for gill flukes and other diseases as the fry are very susceptible at this time.
For those looking to delve and read more about breeding Discus, stay tuned for an upcoming article we have
Discus Fish Diseases
Discus can be affected by a variety of diseases, and, unlike Neon Tetra, they don’t have any well-known diseases particular to them.
Let’s start by the most common causes of Discus afflictions. Discus’ getting sick is almost always due to the introduction of some contaminant to the water. The two most common causes of this are introducing another sick fish or introducing contaminated food (i.e through live food).
Some of the most common diseases are fungal infections, parasites, and ich. Some other common issues and causes of symptoms are improper water parameters. Here are some symptoms worth paying attention too:
- Fungus. Fungus can attach to your Discus and start growing. It’ll be visible by its cotton-like appearance on the surface of the Discus’ skin.
- Rubbing. Discus, when they’re fighting against a parasite, can start rubbing themselves around the tank to “itch”. Look to see if your Discus seems lethargic but rubs itself on the decorations.
- Clamped fins / change of diet. Discus love good food and look bright with spread fins when healthy. If they clamp their fins, darken in color, and refuse to eat, this could be a sign of disease.
- Anything else that seems abnormal. For example, a rotting fin, body ulcers, white string feces, and looking like they’re covered in specks or a carpet.
- Discus Plague – its existence is hotly debated in the Discus realm, but it’s a disease that presents normally with a carpet-like coating on the Discus and extra slime coat production. Supposedly, any survivors of the disease are life-long carriers and it can travel in the air between tanks.
Generally, treatment options vary depending on the disease and are too numerous to discuss in this article. However, if you notice one or more of the above symptoms, I recommend quarantining the Discus from your other Discus and looking up a treatment option based on the symptoms. Google or aquarium forums are your friend here.
Hopefully you never have to deal with any particularly horrible Discus diseases.
Discus Fish Lifespan
The last thing I want to discuss is the lifespan of Discus.
Discus average a lifespan of roughly 10 years, however, they can live up to 15 years. This is important, because this means they can live as long as dogs, cats, or other household pets.
It’s worth keeping in mind when you start a Discus aquarium that 15 years is a long time. If you choose to move 500 miles during this time, you’ll need to find a way to pack up and ship the Discus. That can be a difficult prospect, so it’s something worth keeping in mind. Especially if you move around every several years.
However, with that said, caring for Discus for their entire lifespan can be an incredibly exciting experience.
Discus fish care is a difficult topic, often surrounded by some mystery. However, Discus are an incredibly intelligent and colorful fish, and can be one of the most rewarding aquarium fish to keep.
The aim of this guide was to teach you everything you need to know, and serve as a Discus Fish care reference. Thank you for taking the time to read it! Please share any questions, comments, or concerns in the comments below. If you enjoyed the guide, please take the time to share it with your aquarist friends.